The invention relates to novel compositions for the oxidation dyeing of keratin fibers, comprising at least one para-aminophenol as oxidation base, to the dyeing process using this composition, to novel para-aminophenols and to a process for their preparation.
It is known to dye keratin fibers, and in particular human hair, with dye compositions containing oxidation dye precursors, in particular ortho- or para-phenylenediamines, ortho- or para-aminophenols and heterocyclic compounds such as diaminopyrazole derivatives, which are generally referred to as oxidation bases. The oxidation dye precursors, or oxidation bases, are colorless or weakly colored compounds which, when combined with oxidizing products, may give rise to colored compounds and dyes by a process of oxidative condensation.
It is also known that the shades obtained with these oxidation bases may be varied by combining them with couplers or coloration modifiers, the latter being selected in particular from aromatic meta-diamines, meta-aminophenols, meta-diphenols and certain heterocyclic compounds.
The variety of molecules used as oxidation bases and couplers makes it possible to obtain a wide range of colors.
The so-called xe2x80x9cpermanentxe2x80x9d coloration obtained by means of these oxidation dyes must moreover satisfy a certain number of requirements. Thus, it must have no toxicological drawbacks and it must allow shades of the desired intensity to be obtained and have good resistance to external agents (light, bad weather, washing, permanent-waving, perspiration and rubbing).
The dyes must also allow white hairs to be covered and, lastly, they must be as unselective as possible, that is to say that they must allow the smallest possible differences in coloration to be produced over the entire length of the same keratin fiber, which may indeed be differently sensitized (i.e. damaged) between its tip and its root.
The inventors have now discovered, entirely surprisingly and unexpectedly, that certain para-aminophenols of formula (I) defined below, for those which are novel per se, are suitable for use as oxidation dye precursors.
This discovery forms the basis of the present invention.
A first subject of the invention is thus a composition for the oxidation dyeing of keratin fibers, and in particular human keratin fibers such as the hair, characterized in that it comprises, in a medium which is suitable for dyeing, as oxidation base, at least one para-aminophenol of formula (I) below, and/or at least one acid-addition salt thereof: 
in which:
R1 represents a hydrogen atom, a linear or branched C1-C4 alkyl radical or a C1-C4 trifluoroalkyl radical,
R2 and R3 independently represent a hydrogen atom, a C1-C4 alkyl radical or a C1-C4 monohydroxyalkyl radical,
X, Y and Z independently represent a carbon, nitrogen, oxygen or sulphur atom,
the bonds XY and YZ can be single or double bonds.
As mentioned above, the oxidation dye compositions in accordance with the invention can produce a coloration on keratin fibers in oxidizing medium.
Another subject of the invention is the use of the para-aminophenols of formula (I) as oxidation base in compositions for the oxidation dyeing of keratin fibers, and in particular human keratin fibers such as the hair.
In general, the acid-addition salts which can be used in the context of the dye compositions of the invention (oxidation bases and couplers) are selected in particular from the hydrochlorides, hydrobromides, sulphates, tartrates, lactates and acetates.
Among the para-aminophenols of formula (I) which can be used as oxidation bases in the compositions in accordance with the invention, mention may be made in particular of:
4-amino-2,2-dimethyl-2,3-dihydrobenzofuran-7-ol,
7-amino-3H-benzoimidazol-4-ol,
7-aminobenzothiophen-4-ol,
7-amino-2,3-dimethylbenzofuran-4-ol,
4-amino-2,3-dimethylbenzofuran-7-ol,
7-amino-1-propyl-5-trifluoromethyl-1H-benzoimidazol-4-ol,
7-aminobenzoisothiazol-4-ol,
7-amino-1H-benzotriazol-4-ol,
4-amino-2,3-dihydro-1H-indol-7-ol,
7-aminoindan-4-ol,
7-amino-5-methyl-2,1,3-benzothiadiazol-4-ol,
7-amino-2,1,3-benzothiadiazol-4-ol,
7-amino-1-methyl-1H-indol-4-ol,
7-amino-1-(2-hydroxyethyl)-1H-indol-4-ol, and the acid-addition salts thereof.
Among these para-aminophenols, the ones more particularly preferred are:
4-amino-2,2-dimethyl-2,3-dihydrobenzofuran-7-ol,
7-amino-3H-benzoimidazol-4-ol,
7-amino-1-methyl-1H-indol-4-ol, and the acid-addition salts thereof.
The para-aminophenol(s) of formula (I) above preferably represent(s) from approximately 0.0005 to approximately 12% by weight relative to the total weight of the dye composition, and even more preferably from approximately 0.005 to approximately 6% by weight.
The medium which is suitable for dyeing (or the support) generally comprises water or a mixture of wafer and at least one organic solvent to solubilize the compounds which would not be sufficiently soluble in water. Organic solvents which may be mentioned, for example, are C1-C4 lower alkanols such as ethanol and isopropanol; glycerol; glycols and glycol ethers such as 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether and monomethyl ether, and aromatic alcohols such as benzyl alcohol or phenoxyethanol, similar products and mixtures thereof.
The solvents may be present in proportions preferably ranging from approximately 1 to approximately 40% by weight relative to the total weight of the dye composition, and even more preferably from approximately 5 to approximately 30% by weight, relative to the total weight of the dye composition.
The pH of the dye composition in accordance with the invention preferably ranges from 3 to 12 and more preferably from 5 to 11. It may be adjusted to the desired value using acidifying or basifying agents usually used in the dyeing of keratin fibers.
Among the acidifying agents which may be mentioned, by way of example, are inorganic or organic acids such as hydrochloric acid, orthophosphoric acid, sulphuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid and lactic acid, and sulphonic acids.
Among the basifying agents which may be mentioned, by way of example, are aqueous ammonia, alkaline carbonates, alkanolamines such as mono-, di- and triethanolamines and derivatives thereof, sodium hydroxide or potassium hydroxide and the compounds of formula (II) below: 
in which:
W is a propylene residue optionally substituted with a hydroxyl group or a C1-C4 alkyl radical;
R4, R5, R6 and R7 independently represent a hydrogen atom or a C1-C4 alkyl or C1-C4 hydroxyalkyl radical.
In addition to the dyes of formula (I) defined above, the dye composition in accordance with the invention can also contain at least one additional oxidation base which can be selected from the oxidation bases conventionally used in oxidation dyeing and among which mention may be made in particular of para-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols and heterocyclic bases other than the para-aminophenols of formula (I) used in accordance with the invention.
Among the para-phenylenediamines, mention may be made more particularly, by way of example, of para-phenylenediamine, para-toluylenediamine, 2,6-dimethyl-para-phenylenediamine, 2-xcex2hydroxyethyl-para-phenylene-diamine, 2-n-propyl-para-phenylenediamine, 2-isopropyl-para-phenylenediamine, N-(xcex2-hydroxypropyl)-para-phenylenediamine, N,N-bis-(xcex2-hydroxyethyl)-para-phenylenediamine, 4-amino-N-(xcex2-methoxyethyl)aniline, and the para-phenylenediamines described in French patent application FR-A-2,630,438, the disclosure of which is specifically incorporated by reference herein, and the acid-addition salts thereof.
Among the bis(phenyl)alkylenediamines, mention may be made more particularly, by way of example, of N,Nxe2x80x2bis(xcex2,hydroxyethyl)-N,Nxe2x80x2-bis(4xe2x80x2-aminophenyl)-1,3-diaminopropanol, N,Nxe2x80x2-bis(xcex2-hydroxyethyl)-N,Nxe2x80x2-bis(4xe2x80x2-aminophenyl)ethylenediamine, N,Nxe2x80x2-bis-(4-aminophenyl)tetramethylenediamine, N,Nxe2x80x2-bis-(xcex2-hydroxyethyl)-N,Nxe2x80x2-bis(4-aminophenyl)-tetramethylenediamine, N,Nxe2x80x2-bis(4-methylaminophenyl)tetramethyiened amine and N,Nxe2x80x2-bis(ethyl)-N,Nxe2x80x2-bis(4xe2x80x2-amino-3xe2x80x2-methylphenyl)ethylenediamine, and the acid-addition salts thereof.
Among the para-aminophenols, mention may be made more particularly, by way of example of para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol and 4-amino-2-(xcex2-hydroxyethylaminomethyl)phenol, and the acid-addition salts thereof.
Among the ortho-aminophenols, mention may be made more particularly, by way of example, of 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and 5-acetamido-2-aminophenol, and the acid-addition salts thereof.
Among the heterocyclic bases, mention may be made more particularly, by way of example, of pyridine derivatives, pyrimidine derivatives and pyrazole derivatives, and the acid-addition salts thereof.
When they are used, these additional oxidation bases preferably represent from approximately 0.0005 to approximately 12% by weight relative to the total weight of the dye composition, and even more preferably from approximately 0.005 to approximately 6% by weight relative.
The oxidation dye compositions in accordance with the invention can also contain at least one coupler and/or at least one direct dye, in particular in order to modify the shades or to enrich them with glints.
The couplers which can be used in the oxidation dye compositions in accordance with the invention can be selected from the couplers used conventionally in oxidation dyeing and among which mention may be made in particular of meta-phenylenediamines, meta-aminophenols, meta-diphenols and heterocyclic couplers such as, for example, indole derivatives, indoline derivatives, pyridine derivatives and pyrazolones, and the acid-addition salts thereof.
These couplers are more particularly selected from 2-methyl-5-aminophenol, 5-N-(xcex2-hydroxyethyl)amino-2-methylphenol, 3-aminophenol, 1,3-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene, 2,4-diamino-1-(xcex2-hydroxyethyloxy)benzene, 2-amino-4-( greater than hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene, 1,3-bis(2,4-diaminophenoxy)propane, sesamol, xcex1-naphthol, 6-hydroxyindole, 4-hydroxyindole, 4-hydroxy-N-methylindole, 6-hydroxyindoline, 2,6-dihydroxy-4-methylpyridine, 1-H-3-methylpyrazol-5-one and 1-phenyl-3-methylpyrazol-5-one, and the acid-addition salts thereof.
When they are present, these couplers preferably represent from approximately 0.0001 to approximately 10%, by weight relative to the total weight of the dye composition, and even more preferably from approximately 0.005 to approximately 5% by weight.
The dye composition according to the invention can also contain various adjuvants used conventionally in compositions for dyeing the hair, such as anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers or mixtures thereof, inorganic or organic thickeners, antioxidants, penetration agents, sequestering agents, fragrances, buffers, dispersing agents, conditioners such as, for example, silicones, film-forming agents, preserving agents and opacifying agents.
Needless to say, a person skilled in the art will take care to select the optional complementary compound(s) mentioned above such that the advantageous properties intrinsically associated with the oxidation dye composition in accordance with the invention are not, or are not substantially, adversely affected by the addition or additions envisaged.
The dye composition according to the invention may be in various forms, such as in the form of liquids, creams, gels or any other form which is suitable for dyeing keratin fibers, and in particular human hair.
A subject of the invention is also a process for dyeing keratin fibers, and in particular human keratin fibers such as the hair, using the dye composition as defined above.
According to this process, at least one dye composition as defined above is applied to the fibers, the color being developed at acidic, neutral or alkaline pH using an oxidizing agent which is added to the dye composition only at the time of use, or which is present in an oxidizing composition that is applied simultaneously or sequentially in a separate manner.
According to a preferred embodiment of the dyeing process according to the invention, the dye composition described above is preferably mixed, at the time of use, with an oxidizing composition containing, in a medium which is suitable for dyeing, at least one oxidizing agent present in an amount which is sufficient to develop a coloration. The mixture obtained is then applied to the keratin fibers and is preferably left in place for approximately 3 to approximately 50 minutes, more preferably approximately 5 to approximately 30 minutes, after which the fibers are rinsed, washed with shampoo, rinsed again and dried.
The oxidizing agent present in the oxidizing composition as defined above may be selected from the oxidizing agents conventionally used for the oxidation dyeing of keratin fibers, and among which mention may be made of hydrogen peroxide, urea peroxide, alkali metal bromates and persalts such as perborates and persulphates. Hydrogen peroxide is particularly preferred.
The pH of the oxidizing composition containing the oxidizing agent as defined above is such that, after mixing with the dye composition, the pH of the resulting composition applied to the keratin.fibers preferably varies from 3 to 12 and even more preferably from 5 to 11. It is adjusted to the desired value using acidifying or basifying agents usually used in the dyeing of keratin fibers and as are defined above.
The oxidizing composition as defined above can also contain various adjuvants used conventionally in compositions for dyeing the hair and as are defined above.
The composition which is finally applied to the keratin fibers may be in various forms, such as in the form of liquids, creams, gels or any other form which is suitable for dyeing keratin fibers, and in particular human hair.
Another subject of the invention is a multi-compartment device or dyeing xe2x80x9ckitxe2x80x9d or any other multi-compartment packaging system, a first compartment of which contains the dye composition as defined above and a second compartment of which contains the oxidizing composition as defined above. These devices may be equipped with a means which makes it possible to deliver the desired mixture onto the hair, such as the devices described in French patent FR-2,586,913, the disclosure of which is specifically incorporated by reference herein.
Certain para-aminophenols of formula (I) used as oxidation bases in the context of the present invention are novel and, in this respect, constitute another subject of the invention.
These novel para-aminophenols are:
4-amino-2,2-dimethyl-2,3-dihydrobenzofuran-7-ol,
7-amino-1-methyl-1H-indol-4-ol, and the acid-addition salts thereof.
The para-aminophenols of formula (I) in accordance with the invention can be prepared, for example, according to the general process corresponding to the following synthetic scheme: 
which includes, in a first step, in basifying an aqueous solution of a phenol of formula (III) in which the radicals R1, R2 and R3 and the atoms X, Y and Z have the same meanings as those given above for formula (I), using a strong base, at a temperature preferably ranging from xe2x88x9215xc2x0 C. to 20xc2x0 C. and more preferably from xe2x88x925xc2x0 C. to 5xc2x0 C., in order to obtain an aqueous solution of the corresponding phenate, and then, in a second step, in reacting the phenate obtained in the first step with a diazonium salt of an aromatic amine while maintaining the temperature of the medium at a temperature preferably ranging from xe2x88x9215xc2x0 C. to 20xc2x0 C. and more preferably from xe2x88x925xc2x0 C. to 5xc2x0 C., in order to obtain the corresponding diazonium compound of formula (IV) in which the radicals R1, R2 and R3 and the atoms X, Y and Z have the same meanings as those given above for formula (I), and then, in a third step, in reducing the diazonium compound of formula (IV), either by chemical reduction or by reduction by catalytic hydrogenation in the presence of an oxidation catalyst and hydrogen or in the presence of a hydrogen donor, in order to obtain the corresponding para-aminophenol of formula (I).
The basifying agent used in the first step is preferably selected from strong bases such as sodium hydroxide and potassium hydroxide.
The aromatic amine used in the second step is preferably selected from anilines that are unsubstituted or mono- or polysubstituted with a C1-C4 alkyl, C1-C4 alkoxy, C1-C4 dialkylamino, nitro, carboxyl or sulphonyl radical.
It is most particularly preferred to use aniline or sulphanilic acid as aromatic amine.
The diazonium salt of the aromatic amine used in the second step is preferably prepared by dissolving the aromatic amine in a solution of strong acid such as, for example, hydrochloric acid, to which a solution of sodium nitrite is then added while maintaining the temperature of the medium at a temperature ranging from xe2x88x9215xc2x0 C. to 20xc2x0 C. and more preferably from xe2x88x925xc2x0 C. to 5xc2x0 C.
When the reduction of the compound of formula (IV) is carried out by chemical reduction, dithionite, iron in acetic medium or zinc in alcoholic medium is preferably used as reducing agent.
When the reduction of the compound of formula (IV) is carried out by catalytic hydrogenation, the hydrogen used according to the process of the invention is preferably molecular hydrogen under low pressure.
Among the hydrogen donors, mention may be made of formic acid and olefinic hydrogen donors such as, for example, cyclohexene, substituted cyclohexenes, 1,3-cyclohexadiene and 1,4-cyclohexadiene.
As hydrogenation catalyst, mention may be made, for example, of metals selected from chromium, molybdenum, tungsten, platinum, palladium, rhodium. cobalt, nickel and ruthenium, oxides thereof and combinations of these substances such as, for example, a mixture of cobalt oxide and molybdenum oxide including cobalt molybdate.
The preferred hydrogenation catalysts are palladium or Raney nickel, as well as other platinum-group metals. In a known manner, the catalyst can be deposited on an inert support of neutral pH so as not to influence the pH of the reaction solvent medium. Among these inert supports, mention may be made, for example, of neutral wood charcoal, neutral charcoal, neutral alumina, zeolites, clays, etc. Neutral charcoal is preferably used.
The hydrogenation catalysts are generally present in an amount ranging from 0.2 to 5% by weight of metal equivalent relative to the weight of the compound of formula (IV) to be reacted.
When the reaction is complete, the para-aminophenols of formula (I) in accordance with the invention can, where appropriate, be recovered by methods well known to those skilled in the art, such as crystallization, distillation or vapour-entrainment.